Fibrous faced ceiling panel

ABSTRACT

A suspension ceiling panel that includes enhanced durability, sound absorption and increased fire safety qualities. The panel comprises a body substrate including a plurality of apertures. The body is further adapted to be connected to the ceiling grid members. The outer exposed surface of the body substrate is covered by a non-woven fibrous material. Apertures in the body substrate in combination with the non-woven fibrous material on the lower exposed surface of the panel provides the appearance of a traditional acoustical panel but provides desirable sound absorption and fire resistive qualities.

BACKGROUND

This disclosure relates to suspended ceiling systems and moreparticularly to a novel and improved system using perforated metalceiling panels that include a non-woven fibrous facing material on thelower exposed surface of the panel creating an aesthetically pleasingand durable with fire safety qualities in a sound absorbing paneledceiling system.

By way of background but not limitation, suspended-ceiling systemstypically include grid members that provide for oppositely extendingceiling panel support flanges. In these systems, the edges of theceiling panels are installed by laying them in the panel opening createdby the grid members. There are also suspended-ceiling systems that havegrid members, which include channels designed to grip the verticallyextending edges of metal ceiling panels. These ceiling panels aretypically installed by snapping the flanges up into the grid memberchannel, and are generally referred to as “snap-up ceiling panels.”Typical lay-in grid panels are manufactured from slag wool fiber and/orrecycled paper and expanded perlite or fiberglass to create light weightaesthetic ceiling panels. Some of these grid panels do not providedurability or sound absorption qualities that are desired for use incommercial, residential and industrial space.

In view of the above, it should be appreciated that there is a need fora ceiling panel that provides for increased durabilty and soundabsorption. The present disclosure satisfies these and other needs andprovides further related advantages.

SUMMARY

The disclosure may be described as a novel and improved suspensionceiling panel that includes enhanced sound deadening qualities andincreased durability. In the preferred embodiment the panel comprises ametallic panel substrate including a plurality of apertures of varyingsizes. The body is further adapted to be connected to the ceiling gridmembers. The outer exposed surface of the metallic panel substrate iscovered by a non-woven fibrous material that is adhered thereto. Themulti-dimensioned apertures formed in the panel substrate in combinationwith the non-woven fibrous fabric on the lower exposed surface of thepanel not only provides the appearance of a traditional acoustical panelbut provides desirable sound absorption and resistance to flame spreadand smoke generation.

Other features and advantages of the disclosure will be set forth inpart in the description which follows and the accompanying drawings,wherein the embodiments of the disclosure are described and shown, andin part will become apparent upon examination of the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features of this disclosure and the mannerof obtaining them will become more apparent and the disclosure will bebest understood by reference to the following description of embodimentsof the disclosure taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a perspective view of one type of ceiling system illustratingfibrous faced ceiling panels;

FIG. 2 is a sectional view of the ceiling system, taken along lines 2-2,illustrating the fibrous faced ceiling panels connected to a gridsystem;

FIG. 3 is a top view of the ceiling panel illustrating the spacing andsizes of the perforations;

FIG. 4 is a top view of the ceiling panel illustrating an alternateperforation pattern;

FIG. 5 is a perspective view of a ceiling system illustrating thefibrous faced ceiling panels transitioning from a first elevation to asecond elevation;

FIG. 6 is another perspective view of a ceiling system illustrating thefibrous faced ceiling panels transitioning from a first elevation to asecond elevation;

FIG. 7 is a perspective view of a ceiling system illustrating thetransition from the fibrous faced ceiling panels to other types ofceiling panels; and

FIG. 8 is a perspective view of a ceiling system illustrating curvedfibrous faced ceiling panels.

DETAILED DESCRIPTION

While the present disclosure will be described fully hereinafter withreference to the accompanying drawings, in which a particular embodimentis shown, it is to be understood at the outset that persons skilled inthe art may modify the disclosure herein described while still achievingthe desired result. Accordingly, the description that follows is to beunderstood as a broad informative disclosure directed to persons skilledin the appropriate art and not as limitations on the present disclosure.

As illustrated in the drawings, FIG. 1 illustrates a portion of anassembled suspension ceiling incorporating snap-up fibrous faced ceilingpanels 10 in accordance with the present disclosure. In such a ceilingpanel system, grid members 12 are interconnected to form a gridstructure 13. The grid members 12 are arranged to form openings 14 sizedto receive the ceiling panels 10. The grid members 12 are suspended fromthe building structure by wire hangers 16 or other supportingstructures.

To create the grid structure 13, a row of parallel evenly spaced gridmembers 12 are suspended by wire hangers 16. Each row of the gridmembers 12 are spaced apart to accommodate the size of the fibrous facedceiling panels 10. To accommodate a 2 foot by 2 foot ceiling panel, thegrid members 12 would be spaced apart 2 feet on-center. The gridstructure 13 also includes a second set of grid members 18 that areperpendicularly oriented in relation to the first set of grid members 12to create the opening required for hanging the panels 10.

The fibrous faced ceiling panels 10 are normally rectangular, usuallysquare in shape, and are preferably made out of metal. The panels 10 aredurable in that they are impact resistant, self-supporting do not sag orfracture when perforated. Depending upon the ceiling design used, it maybe desirable to shape the panels 10 into a square or curved shape, asshown in FIG. 8, but other shapes may be utilized. Other shapes wouldinclude transition panels, as shown in FIGS. 5 and 6, which allow thetransition from a first elevation to a second elevation. FIG. 7illustrates a decorative transition panel 55 without the facer material,which can be a low gloss or high gloss, reflective panel. While thepreferred material used in fabricating the fibrous faced ceiling panels10 is metal, other materials may be used including gypsum, wood, woodfiber, plastic and other substrate materials that allows perforationwhile retaining the basic shape and stiffness of the fibrous facedceiling panels 10. Metal and plastic material, such as polycarbonate,are preferred since panels can be molded or stamped to include a desiredshape or to form various edge configurations for connection to the gridstructure 13. The fibrous faced ceiling panels 10 include an interiorface 20 and an exterior face 22. The panels 10 may also include a hinge24 along a first corner 25 of the panel 10 to permit the panel to bepivoted to an open position with respect to the grid system 13. Thepanel 10 preferably includes flanges 26 along the edges 58 of the panel10. While a flanged edge and a hinged edge are disclosed, other edgeconfigurations may be used to secure the panels 10 to the grid system.

The fibrous faced ceiling panels 10, as shown in FIG. 1, illustrates thepanels 10 connected to the grid structure 13 by use of flanges 26. It isbeneficial to use the hinge 24 to support the ceiling panel 10 when allmetal ceiling panels become as large as 4 feet by 4 feet, because thepanels become awkward to install and remove due to their relativelylarge size and weight. Further illustrations of the use of a hinge canbe found in U.S. Pat. No. 6,467,228, incorporated herein by reference.When working with a piece of sheet metal with such a large surface, anyimproper handling may result in damage to the overall finish of theceiling panel 10. Also, by using the hinge 24 that spans the length ofthe ceiling panel 10, the weight of the panel is evenly distributedacross the entire corner 25 of the panel 10, preventing rippling thatwould be apparent in the bottom surface 20 of the panel 10. Furthermore,once the ceiling panel 10 is connected to the grid members 12, theceiling panel 10 will automatically be in alignment to allow for easyclosure by pivoting the ceiling panel 10 upward and snapping in theflanges 26 into the grid.

FIG. 2 is a cross section of FIG. 1 taken along line 2-2 looking in thedirection of the arrows and shows the grid member 12 and the hinge 24along an corner 25 of a first ceiling panel 10 and the flanged edge 26of a second ceiling panel 10. The grid member in this example 12 isfabricated out of a single piece of die-formed sheet metal. The gridmember 12 after fabrication includes a bulb portion 34, a channel 36 anda double layer bridge portion 38 that connects the bulb portion 34 andthe channel 36. The overall shape of the grid member 12 is to give themember 12 strength to prevent flexing. Typically, apertures (not shown)are placed along the length of the bridge portion 38 so that wirehangers 16 can be threaded through and wrapped around the bulb portion34. Once the wire hanger 16, as shown in FIG. 1, which can be in theform of a wire, is threaded through an aperture (not shown) and aroundthe bulb portion 34, the wire hanger 16 is wrapped around itself severaltimes to prevent it from unraveling.

The bridge portion 38 typically includes slots (not shown) that allowone grid member 12 to be connected to the second grid member 18 to formthe grid structure 13. The channel 36, as shown in FIG. 2 is formed bybending the double layers of the bridge portion 38, 90 degrees outward,90 degrees downward and 90 degrees inward to form a boxed channel 36.Bottom edges 42 are folded over to act as an engagement edge for theflange 26 and a retaining surface for the hinge 24. The hinge 24 isformed in the ceiling panel 10 by die-forming the hinge 24 90 degreesupward to create an upwardly extending leg 43 and then die-forming theedge 90 degrees inward to create an inward lip 44. The inward lip 44 ofthe hinge 24 rests upon the bottom edge 42 in the channel 36 of the gridmember 12. The flange 26, shown in FIG. 2, is formed by die-forming ormolding the edge 26 of the ceiling panel 10 upward 90 degrees to form avertical member 45 and by forming a rib 48. The ceiling panel 10 isretained to the grid structure 13 by forcing rib 48 past the bottom edge42. The rib 48 is properly positioned within the channel 36 when the rib48 is resting upon the bottom edge 42. The vertical member 45 biases therib 48 to prevent the ceiling panel 10 from moving out of position.While use of an edge with a rib 48 is preferred, other grid engagementmechanisms may be used including a lay-in arrangement wherein the edges26 do not include a flange.

FIG. 2 also illustrates a fibrous facer material 54 adhered to theexterior face 22 of the panel substrate 11 viewable from theenvironmental area of a building structure. The environmental area ofthe building structure is defined as the space within a building used byoccupants to work or conduct other activities. It is the inhabitablespace within a structure. From the environmental area, the fibrous facermaterial 54 is substantially exposed and viewable by the occupantsbelow. The interior face 20 of the panel 10 is substantially concealedfrom the environmental area and is not viewable by the occupants below.The fibrous facer material 54 creates an aesthetically pleasing surfacethat gives the ceiling a soft appearance as opposed to a paintedmetallic ceiling panel, which has an undesirable shiny appearance.

FIG. 3 is a top view of the fibrous faced ceiling panel 10 thatillustrates the positioning of apertures 52 of a first diameter andapertures 53 of a second diameter across the panel 10. The non-wovenfibrous facer material 54 on the exterior face 22 of the panel 10 isadapted to cover the entire face 22 of the panel 10 including theapertures 52, 53. When the fibrous facer material 54 is applied to thepanel 10, only the fibrous facer material 54 is visible from below. Thepanel substrate 11 or the apertures 52, 53 are not viewable from below.The sound absorption mechanism of the fibrous faced ceiling panels 10 isa combination of resonant absorber sound attenuation due to theresistance in air flow through the pores of the non-woven fibrous facermaterial 54 and the perforation of the panel 10. In order to maximizesound absorption at varying frequencies, three main parameters need tobe optimized. This includes the extent of perforation of the panel 10with apertures 52, the airflow resistance of the fibrous facer material54 and the plenum height, i.e. the distance between the structure andthe ceiling.

FIG. 4 illustrates a top view of an alternate aperture arrangementwherein the panel 10 includes apertures 52 of a first diameter apertures53 of a second diameter and apertures 55 of a third diameter. Thecombination of the three aperture sizes enhances the resistance of soundwaves of varying frequency. The apertures 52 shown in FIG. 1 are all ofa uniform size.

The extent of the perforation of the panel 10 is partially dependentupon the strength of the selected substrate material and its resistanceto mechanical impact and to excessive panel flex. Substrates such asmetal and plastic can be extensively perforated, while gypsum board islimited to no more than about 20% of its surface area in order tomaintain strength. In order to achieve the proper sound deadeningqualities, the substrate is perforated from about 10% to about 35% openarea. Optimally, the percentage of the open area of the face 50 of thepanel 10 should be about 30% to about 33%.

Sound is made up of various frequencies. A cymbal for instance wouldemit a high frequency whereas a base drum would emit a low frequency.The varying amplitude of the frequencies renders it difficult to providea medium that is sufficient at deadening sound. A particular media maybe efficient at capturing low frequency noise but is incapable ofcapturing high frequency noise. In order to enhance sound absorption atdifferent frequencies the substrate panel 11 is perforated withapertures of different diameters. More specifically, two or threedifferent aperture sizes are preferred. For the panel 10 to achieve thedesired sound deadening qualities, the diameter of the apertures in thepanel are from about 0.039 inches to about 0.117 inches to achieve thedesired sound deadening qualities. Preferably, the perforated pattern isa combination of 15/128 of an inch apertures and 3/32 of an inchapertures. While circular apertures are preferred, oval triangular,polygonal, square or elliptical shaped apertures can also be used.Apertures with large diameters permit the passage of low frequencysounds with large amplitudes whereas apertures with smaller diameterspermit the passage of high frequency sounds with smaller amplitudes.

Spacing between the panels 10 is important in order to gain the maximumbenefits from the panels. In order to maximize the sound absorptionqualities of the panels, it is sufficient that the gap tolerance betweenpanels is in the range from about zero gap to about ⅜ of an inch andpreferably from about a zero gap to a gap of about ¼ of an inch. Spacingbetween the panels larger than ⅜ of an inch permits excessive sound tobe deflected off of the grids 12 and back into the room, reducing theeffectiveness of the ceiling system.

In testing of the panel 10 of the present disclosure smoke developmentand flame spread by the panel resulted in values substantially lowerthan industry standards. Limiting smoke development in a building fireis essential in order to increase the ability for occupants in the buildto escape without being subjected to smoke inhalation. Typically in afire, smoke inhalation, and not the fire itself cause death to theoccupants.

The non-woven fibrous facer material 54 is applied to the panelsubstrate with use of an adhesive. The adhesive utilized to adhere thenon-woven fibrous facer material 54 to the ceiling panel 10 ispreferably a hot melt adhesive that is substrate compatible. Theadhesive must also be compatible with the type of facer material 54applied to the panel 10. While hot melt adhesive is preferred, it isforeseeable that other types of adhesives, such as spray, brush orroll-on adhesives may be used. The sound absorption qualities of thepanel are also varied by the type and amount of the glue used on thefibrous facer material 54.

The panel substrate 11 and fibrous facer material 54 are designed topermit molding or stamping of the panel 10 into desired configurationsto create flanges 26. Transition panels 57, as shown in FIGS. 5 and 6 orcurved ceiling panels, as shown in FIG. 8 may also be created by moldingor stamping the panel. Transition panels 57 are used to transition froma first ceiling elevation to a second ceiling elevation and can beformed by bending or curving the panels 10. In order to permit the panel10 to be formed into the desired configuration, the panel substrate 11is preferably made from steel, aluminum or polymer. The fibrous facermaterial 54 used to cover the exterior face 51 of the panel substrate 11can be of various materials so long as the material does not rip or tearwhen formed with the panel. Certain materials when tested such asfiberglass tear or crack when the panel 10 is molded to create flanges26 or other desired shapes. Preferred materials for use as a fibrousface material 54 include polymer mixtures having polyster fibers.Another such usable material is a combination of NYLON6 andPolyethylene. Polymer mixtures of fibrous materials, permit the passageof airflow through the material 54 and allow the panel 10 to be shapedafter the fibrous material 54 has been adhered to the panel 10 withouttearing the fibrous face material 54.

To achieve the desired sound deadening qualities, the panel substrate11, in combination with the fibrous facer material 54 should have anairflow resistance from about 900 mks rayls to about 1050 mks rayls.Specific airflow resistance is the product of the airflow resistance ofa specimen and its area. This is equivalent to the air pressuredifference across the panel 10 divided by the linear velocity of airflowmeasured outside the panel 10. The airflow resistance of the fibrousfacer material 54 in combination with the perforated panel substrate iscritical to the efficiency of the acoustic attenuation process. If theairflow resistance is too high, the material reflects the sound wave asif it were a solid wall. If it is too low, the sound wave freely travelsthrough the material. In either case the sound attenuation is less thanoptimum. The preferred airflow resistance of the facer material 54should be about 100 mks rayls to about 600 mks rayls.

Airflow resistance of a panel 10 is defined as the ratio of the pressuredrop across the material to the velocity of the gas passing through itand can be expressed in cgs rayls (dyne/cm² per cm/sec). Determinationof flow resistivity is the main property in describing the acousticalperformance of any porous material. Every fibrous material has specificflow resistance characteristics based on its manufacturing process orinherent nature. In the case of composite materials, such as the presentpanel 10, which is a combination of the fibrous facer material 54 andthe perforated panel 10, it is important to understand the individualflow resistance of each component. However, for optimum performance ofthe resultant panel 10, it is vital to tune the flow resistance of theentire system fibrous facer material 54 and panel substrate 11 tomaximize sound absorption. As previously stated, this optimum airflowresistance is about 900 mgs rayls to about 950 mks rayls.

In most cases, plenum height 64 behind the panel 10 is limited andtherefore the sound absorption performance of the panel 10 is restrictedby the short plenum gap, as shown in FIG. 2. In order to further enhancethe sound absorption of the panel 10 with a short plenum height a secondlayer of porous insulation material 56 such as glass fiber, mineralfiber, thermoplastic polymeric fiber, thermosetting polymeric fiber,carbonaceous fiber, milkweed fiber, or foam insulation, (with preferenceto polyolefin microfiber melt blow products) can be applied to theinterior face 20 of the panel 10.

The panels 10 are designed with four edges 58 that are adapted to beconnected to the grid structure 13. The panels 10 can be connected tothe grid structure 13 using various edge configurations. The edges 58 ofthe panel 10 can include the vertical member 45 and a rib member 48.This allows the panel to be snapped into the bottom edges 42 of the gridmembers 12 and 18. In yet another alternative, the panel 10 does notinclude edges 25 and simply lays into the openings 14 created by thegrid structure 13.

While the concepts of the present disclosure have been illustrated anddescribed in detail in the drawings and foregoing description, such anillustration and description is to be considered as exemplary and notrestrictive in character, it being understood that only the illustrativeembodiments have been shown and described and that all changes andmodifications that come within the spirit of the disclosure are desiredand protected.

There are a plurality of advantages that may be inferred from thepresent disclosure arising from the various features of the apparatus,systems and methods described herein. It will be noted that alternativeembodiments of each of the apparatus, systems, and methods of thepresent disclosure may not include all of the features described yetstill benefit from at least some of the inferred advantages of suchfeatures. Those of ordinary skill in the art may readily devise theirown implementations of an apparatus, system, and method that incorporateone or more of the features of the present disclosure and fall withinthe spirit and scope of the invention as defined by the appended claims.

1. A durable sound absorbing panel having surface burning resistancequalities for use in a structure having a usable area, the panelcomprising: a panel substrate having a first face and a second face, thesecond face opposing the first face and substantially concealed from theenvironmental area when installed; the panel substrate, supportable froma structure, the panel substrate including a plurality of aperturesspread across the surface of the panel substrate; a non-woven fibrousmaterial attached to the first face of the panel substrate and appliedsuch that the apertures are covered by the non-woven fibrous material;the non-woven fibrous material is positioned such that nearly completeexposure of the material occurs when installed, permitting viewing fromthe environmental area of the structure.
 2. The sound absorbing andsurface burn resistant panel of claim 1, wherein the non-woven fibrousmaterial is attached to the first face of the panel substrate with anadhesive.
 3. The sound absorbing and surface burn resistant panel ofclaim 1, wherein the apertures include a first group having a first sizeand a second group having a second size.
 4. The sound absorbing andsurface burn resistant panel of claim 3, wherein the apertures havesizes ranging from about 0.039 inches to about 0.117 inches.
 5. Thesound absorbing and surface burn resistant panel of claim 1, wherein theairflow rate resistance through the panel is about 900 mks rayls toabout 1050 mks rayls.
 6. The sound absorbing and surface burn resistantpanel of claim 1, wherein the airflow rate resistance through thenon-woven fibrous material is about 100 mks rayls to about 600 mksrayls.
 7. The sound absorbing and surface burn resistant panel of claim1, wherein the panel includes at least two side edges, each having aflange for connection to a suspended ceiling grid, wherein the suspendedceiling grid includes a plurality of grid members interconnected to formpanel openings, the grid members suspended from the structure withhangers.
 8. The sound absorbing and surface burn resistant panel ofclaim 3, wherein the apertures include a third group having a thirdsize.
 9. An interior finishing panel for use in a building structurecomprising: a semi-rigid panel substrate adapted to be supported by itsedges with minimal panel substrate flex, the panel substrate having afirst face and a second face opposing the first face, the second facebeing substantially concealed when the finishing panel is installedwithin the building structure; a first set of apertures in the panelsubstrate having a first size; a non-woven fibrous material attached tothe first face of the panel substrate covering the first set ofapertures, the fibrous material being substantially visible wheninstalled in the building structure.
 10. The interior finishing panel ofclaim 9, wherein the non-woven fibrous material is attached to the firstface of the panel substrate with an adhesive.
 11. The interior finishingpanel of claim 9, wherein the apertures have sizes ranging from about0.039 inches to about 0.117 inches.
 12. The interior finishing panel ofclaim 9, wherein the airflow rate resistance through the panel is about900 mks rayls to about 1050 mks rayls.
 13. The interior finishing panelof claim 9, wherein the airflow rate resistance through the non-wovenfibrous material is about 100 mks rayls to about 600 mks rayls.
 14. Theinterior finishing panel of claim 9, wherein the panel includes at leasttwo side edges each having a flange for connection to a suspendedceiling grid, wherein the suspended ceiling grid includes a plurality ofgrid members interconnected to form panel openings, the grid memberssuspended from the structure with hangers.
 15. The interior finishingpanel of claim 9, wherein the panel includes a second set of aperturesformed on the panel substrate having a second size.
 16. The interiorfinishing panel of claim 9, wherein the panel includes a third set ofapertures formed on the panel substrate having a third size.
 17. Aninterior finishing panel for use in a building structure comprising: asemi-rigid panel substrate having an exterior face and an interior face,opposing the exterior face, the interior face is adapted to besubstantially concealed when the panel is installed in the buildingstructure; a plurality of apertures having a first size passing throughthe panel substrate and extending across the faces; a non-woven fibrousmaterial adhered to the exterior face of the panel substrate, andpositioned to cover the apertures, the fibrous material is adapted to besubstantially visible when the panel is installed in the buildingstructure.
 18. The interior finishing panel of claim 17, wherein thenon-woven fibrous material is attached to the exterior face of the panelsubstrate with an adhesive.
 19. The interior finishing panel of claim17, wherein the apertures have sizes ranging from about 0.039 inches toabout 0.117 inches.
 20. The interior finishing panel of claim 9, whereinthe airflow resistance rate through the panel is about 900 mks rayls toabout 1050 mks rayls.
 21. The interior finishing panel of claim 17,wherein the airflow resistance rate through the non-woven fibrousmaterial is about 100 mks rayls to about 600 mks rayls.
 22. The interiorfinishing panel of claim 17, wherein the panel include at least two sideedges each having a flange for connection to a suspended ceiling grid,wherein the suspended ceiling grid includes a plurality of grid membersinterconnected to form panel openings, the grid members suspended fromthe structure with hangers.
 23. The interior finishing panel of claim17, wherein the panel includes a second set of apertures passing throughthe panel substrate having a second size.
 24. The interior finishingpanel of claim 17, wherein the panel includes a third set of aperturesformed on the panel substrate having a third size.
 25. A durable soundabsorbing ceiling system having fire resistive qualities for use in astructure having a usable area, the panel comprising: a plurality ofgrid members interconnected to form a grid, the grid members adapted tobe suspended from the structure; a panel substrate having a first faceand a second face, the second face opposing the first face andsubstantially concealed from the environmental area when installed; thepanel substrate, supportable from the grid, the panel substrateincluding a plurality of apertures spread across the surface of thepanel substrate; a non-woven fibrous material attached to the first faceof the panel substrate and applied such that the apertures are coveredby the non-woven fibrous material; the non-woven fibrous material ispositioned such that nearly complete exposure of the material occurswhen installed, permitting viewing from the environmental area of thestructure.
 26. The durable sound absorbing ceiling system of claim 25,wherein the non-woven fibrous material is attached to the first face ofthe panel substrate with an adhesive.
 27. The durable sound absorbingceiling system of claim 25, wherein the apertures include a first grouphaving a first size and a second group having a second size.
 28. Thedurable sound absorbing ceiling system of claim 27, wherein theapertures have sizes ranging from about 0.039 inches to about 0.117inches.
 29. The durable sound absorbing ceiling system of claim 25,wherein the airflow rate resistance through the panel is about 900 mksrayls to about 1050 mks rayls.
 30. The durable sound absorbing ceilingsystem of claim 1, wherein the airflow rate resistance through thenon-woven fibrous material is about 100 mks rayls to about 600 mksrayls.
 31. The durable sound absorbing ceiling system of claim 25,wherein the panel includes at least two side edges, each having a flangefor connection to a suspended ceiling grid, wherein the suspendedceiling grid includes a plurality of grid members interconnected to formpanel openings, the grid members suspended from the structure withhangers.
 32. The durable sound absorbing ceiling system of claim 27,wherein the apertures include a third group having a third size.
 33. Thedurable sound absorbing ceiling system of claim 25, wherein the secondface includes a layer of porous insulation material.
 34. The durablesound absorbing ceiling system of claim 25, wherein the apertures areselected from a group consisting of circular, square, triangular,rectangular and oval.